1. Field of the Invention
The present invention relates to an inflatable curtain designed to protect the occupants of a vehicle during a side impact collision. More specifically, the invention relates to an expandable section in an inflatable curtain that compensates for horizontal contraction of the inflatable curtain during deployment.
2. Description of Related Art
In low-speed automobile collisions, occupants wearing safety belts are generally prevented from impact with the car""s interior objects, such as the windshield, instrument panel, or steering wheel. In more severe collisions, however, even belted occupants may impact the car""s interior objects because their forward motion is so great that they contact these objects before the belts can bring them to a complete stop.
Vehicle manufacturers and suppliers have developed air bag systems, including side impact air bag systems, to supplement safety belts by reducing the chances of contact with the vehicle""s interior objects. In addition, to the extent that such contact cannot be prevented, air bag systems have been designed to distribute the impact more evenly over an occupant""s head and torso.
A side impact air bag system typically consists of three parts: an inflatable curtain, an inflator, and a sensor mechanism. The inflatable curtain is typically made of a thin nylon fabric, and may be compacted by accordion folding, rolling, or any other suitable method, and mounted within a housing located in the vehicle over the doors. The inflatable curtain is typically in communication with the inflator, which is typically in communication with the sensor mechanism. A chemical compound and/or compressed gas may be sealed inside the inflator. After impact of sufficient severity, the sensor mechanism detects the sudden deceleration and sends an electrical signal to the inflator. The inflator then produces gas which inflates the inflatable curtain. As an occupant contacts the inflatable curtain, the gas is vented through openings in the sides of the inflatable curtain, thus absorbing the motion of the occupant""s impact.
An inflatable curtain typically includes an inflatable portion, which may include one or more inflation chambers. An inflatable curtain typically also includes a non-inflatable portion. Adjacent inflation chambers are typically separated by part of the non-inflatable portion. Deployment of the inflatable curtain typically causes the inflation chambers to contract in a horizontal direction. Contraction of the inflation chambers during deployment may cause the inflation chambers to move out of position, thereby reducing the amount of protection that can be provided to a vehicle occupant during a collision.
One known solution to this problem involves cutting away the non-inflatable portion of the inflatable curtain between adjacent inflation chambers, thereby creating an opening. A connection fabric is then attached to the inflatable curtain inside the opening. The connection fabric has a length that is greater than the length of the opening. This allows the connection fabric to expand during deployment, thereby compensating for the contraction that occurs during deployment. This approach, however, requires that a certain amount of fabric be wasted (i.e., the part of the non-inflatable portion that is cut away), which can be expensive in terms of both material costs and labor. This approach also requires that the connection fabric be slack prior to deployment, which can make it difficult to compact the inflatable curtain in order to store it in the vehicle.
Accordingly, it would be an advancement in the art to provide a way to compensate for contraction that occurs in an inflatable curtain during deployment without requiring that a certain amount of fabric be wasted, and without adding to the complexity involved in storing the inflatable curtain in the vehicle prior to deployment. The present invention provides these advancements in a novel and useful way.
The apparatus of the present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available inflatable curtains. In accordance with the invention as embodied and broadly described herein, an inflatable curtain for protecting the occupants of a vehicle during a collision is provided.
According to one configuration, the inflatable curtain may include an inflatable portion. The inflatable portion may include a plurality of inflation chambers. The length of each inflation chamber will be referred to herein as a span length. The distance between adjacent inflation chambers will be referred to herein as a separation length. The inflatable portion may also include an inflation inlet for communication with an inflator.
The inflatable curtain may also include a non-inflatable portion. The non-inflatable portion may include one or more expandable sections disposed between adjacent inflation chambers.
Deployment of the inflatable curtain typically causes the inflation chambers to contract in a horizontal direction. Thus, the span length of each inflation chamber typically decreases during deployment. Advantageously, deployment of the inflatable curtain also causes each of the expandable sections to expand horizontally. Thus, the separation length between adjacent inflation chambers increases during deployment, compensating for the contraction that occurs in the inflation chambers. In one embodiment, the expandable sections may be configured so that the total length of the inflatable curtain remains substantially unchanged during deployment.
An expandable section may include a pleat that unfolds during deployment of the inflatable curtain. In one embodiment, an expandable section may include two layers, a first layer and a second layer. The first layer may include a first slit and a first edge adjacent the first slit. Similarly, the second layer may include a second slit and a second edge adjacent the second slit. The pleat may be formed by folding the second layer so that the second edge is aligned with the first edge.
In such an embodiment, a secure fastening mechanism may be provided to fasten the first edge to the second edge. The secure fastening mechanism may cause the first edge to remain fastened to the second edge after deployment of the inflatable curtain. The secure fastening mechanism may take the form of an attachment seam sewn through the first edge and the second edge.
In addition, a severable fastening mechanism may be provided which causes the pleat to remain folded prior to deployment of the inflatable curtain and which allows the pleat to unfold during deployment of the inflatable curtain. The severable fastening mechanism may take the form of a tear seam sewn through the pleat.
These and other features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.